Config update

Copy fixes from owncloud/documentation#594 and apply them onto config.sample.php

@carlaschroder Have a look at a96f7c1 I added some fixes. Are you fine with them?

cc @PVince81 @wakeup @DeepDiver1975 @LukasReschke 
@LukasReschke Isn't it also crucial for security stuff? (has rules for access deny of data folder) And adding large file upload support is also by adding the config switches to your apache conf.